Answer:
80 mph
Step-by-step explanation:
![\boxed{\sf Distance=Speed \times Time}](https://tex.z-dn.net/?f=%5Cboxed%7B%5Csf%20Distance%3DSpeed%20%5Ctimes%20Time%7D)
<u>First leg of trip</u>
- Speed = 64 mph
- Time = 3 hours
![\implies \sf Distance =64\times 3 = 192\:miles](https://tex.z-dn.net/?f=%5Cimplies%20%5Csf%20Distance%20%3D64%5Ctimes%203%20%3D%20192%5C%3Amiles)
<u>Second leg of trip</u>
- Speed = 92 mph
- Time = 4 hours
![\implies \sf Distance=92 \times 4 = 368\:miles](https://tex.z-dn.net/?f=%5Cimplies%20%5Csf%20Distance%3D92%20%5Ctimes%204%20%3D%20368%5C%3Amiles)
![\boxed{\sf Speed=\dfrac{Distance}{Time}}](https://tex.z-dn.net/?f=%5Cboxed%7B%5Csf%20Speed%3D%5Cdfrac%7BDistance%7D%7BTime%7D%7D)
To find the average speed:
![\begin{aligned}\implies \sf Average\:speed & = \sf \dfrac{Total\:distance}{Total\:time}\\\\ & = \sf \dfrac{192+368}{3+4}\\\\& = \sf \dfrac{560}{7}\\\\ & = \sf 80\:mph\end{aligned}](https://tex.z-dn.net/?f=%5Cbegin%7Baligned%7D%5Cimplies%20%5Csf%20Average%5C%3Aspeed%20%26%20%3D%20%5Csf%20%5Cdfrac%7BTotal%5C%3Adistance%7D%7BTotal%5C%3Atime%7D%5C%5C%5C%5C%20%26%20%3D%20%5Csf%20%5Cdfrac%7B192%2B368%7D%7B3%2B4%7D%5C%5C%5C%5C%26%20%3D%20%5Csf%20%5Cdfrac%7B560%7D%7B7%7D%5C%5C%5C%5C%20%26%20%3D%20%5Csf%2080%5C%3Amph%5Cend%7Baligned%7D)
well, we know the ceiling is 6+2/3 high, and Eduardo has 4+1/2 yards only, how much more does he need, well, is simply their difference, let's firstly convert the mixed fractions to improper fractions and then subtract.
![\stackrel{mixed}{6\frac{2}{3}}\implies \cfrac{6\cdot 3+2}{3}\implies \stackrel{improper}{\cfrac{20}{3}} ~\hfill \stackrel{mixed}{4\frac{1}{2}}\implies \cfrac{4\cdot 2+1}{2}\implies \stackrel{improper}{\cfrac{9}{2}} \\\\[-0.35em] ~\dotfill\\\\ \cfrac{20}{3}-\cfrac{9}{2}\implies \stackrel{using ~~\stackrel{LCD}{6}}{\cfrac{(2\cdot 20)-(3\cdot 9)}{6}}\implies \cfrac{40-27}{6}\implies \cfrac{13}{6}\implies\blacktriangleright 2\frac{1}{6} \blacktriangleleft](https://tex.z-dn.net/?f=%5Cstackrel%7Bmixed%7D%7B6%5Cfrac%7B2%7D%7B3%7D%7D%5Cimplies%20%5Ccfrac%7B6%5Ccdot%203%2B2%7D%7B3%7D%5Cimplies%20%5Cstackrel%7Bimproper%7D%7B%5Ccfrac%7B20%7D%7B3%7D%7D%20~%5Chfill%20%5Cstackrel%7Bmixed%7D%7B4%5Cfrac%7B1%7D%7B2%7D%7D%5Cimplies%20%5Ccfrac%7B4%5Ccdot%202%2B1%7D%7B2%7D%5Cimplies%20%5Cstackrel%7Bimproper%7D%7B%5Ccfrac%7B9%7D%7B2%7D%7D%20%5C%5C%5C%5C%5B-0.35em%5D%20~%5Cdotfill%5C%5C%5C%5C%20%5Ccfrac%7B20%7D%7B3%7D-%5Ccfrac%7B9%7D%7B2%7D%5Cimplies%20%5Cstackrel%7Busing%20~~%5Cstackrel%7BLCD%7D%7B6%7D%7D%7B%5Ccfrac%7B%282%5Ccdot%2020%29-%283%5Ccdot%209%29%7D%7B6%7D%7D%5Cimplies%20%5Ccfrac%7B40-27%7D%7B6%7D%5Cimplies%20%5Ccfrac%7B13%7D%7B6%7D%5Cimplies%5Cblacktriangleright%202%5Cfrac%7B1%7D%7B6%7D%20%5Cblacktriangleleft)
70% of the people were adults
First you subtract 1500-450 = 1050
Then you divide 1050/1500 = .7
Answer:
D. 11
Step-by-step explanation:
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